The beta-cyclodextrin functionalized SBA-15 was synthesized and employed for the fabrication of modified carbon paste electrodes. The electrochemical behavior of o-nitrophenol (o-NP), m-nitrophenol (m-NP) and p-nitrophenol (p-NP) was investigated at the modified electrode. Due to the inhibition of bonded cyclodextrin, the electrode reaction of nitrophenol was interrupted at hydroxylaminophenol stage, three nitrophenol isomers can be discriminated simultaneously according to the different potential of nitrosophenol/hydroxylaminophenol redox reaction. Therefore, low detection limits of 1.0 x 10(-8) mol L(-1) for o-NP and p-NP, 5.0 x 10(-8) mol L(-1) for m-NP were obtained, the linear ranges of the calibration curves are 2.0 x 10(-7) to 1.4 x 10(-6) mol L(-1), 2.0 x 10(-7) to 1.6 x 10(-6) mol L(-1) and 2.0 x 10(-7) to 1.4 x 10(-6) mol L(-1), respectively. Consequently, a selective nitrophenol isomers electrochemical sensor was successfully fabricated and a sensitive method was developed for the determination of o-NP, m-NP and p-NP in aqueous solution simultaneously. (C) 2011 Elsevier Ltd. All rights reserved.